Compounding polymeric compositions (e.g., polymeric films) with various particulate additives can improve their mechanical properties, such as hardness, scratch resistance, wear resistance, and abrasion resistance. The mechanical properties of the composition typically improve in proportion to the amount of particulate added. At a certain point, however, as the amount of the particulate increase, the optical properties of the composition, such as transparency, begin to degrade.
For example, three properties that determine the transparency of a particulate loaded polymeric composition are the particulate particle size, the difference between the refractive indexes of the composition and of the particulate, and the degree of dispersion of particulates throughout a polymeric composition. If a particulate additive has a size greater than the wavelength of visible light, the increasing addition of the particulate additive causes haze and eventually opacity. Likewise, inefficient particulate dispersion results in the clustering of added particulates in the polymeric composition thus leading to higher haze and lower transparency. Therefore, in transparent material systems the achievable mechanical property enhancements of particulate loaded polymeric compositions are limited. Either transparent films with limited, improved mechanical properties, or hazy-opaque films with improved mechanical properties are obtained.
Consequently, there is a need for particulate-filled compositions, such as polymeric films and coatings that exhibit improved combinations of physical and other properties.